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Short Citation:
Office for Coastal Management, 2023: 2017 NOAA NGS Topobathy Lidar DEM: St. Jeromes Creek, MD, https://www.fisheries.noaa.gov/inport/item/56773.

Item Identification

Title: 2017 NOAA NGS Topobathy Lidar DEM: St. Jeromes Creek, MD
Short Name: NOAA_MD1702_Topobathy_DEM.xml
Status: Completed
Publication Date: 2019
Abstract:

This data was collected by NOAA using a Riegl VQ880G sensor. The data was acquired August 5, 2017. The data includes topobathy data in LAS 1.2 format classified as created,unclassified (1); ground (2); topographic noise (7); bathymetric noise (22); water column (25); bathymetric bottom (26); water surface (27); International Hydrographic Organization S-57 object; not otherwise specified (30), in accordance with project specifications. The project consists of approximately 34 square miles of data along the shores of St. Jeromes Creek. This dataset contains 342 500 m x 500 m lidar tiles.

Purpose:

St. Jeromes Creek has been identified as having critical topographic and bathymetric data gaps by NOAA. This lidar data will fill those critical gaps.

Supplemental Information:

The full workflow used for this project is found in the final project report submitted to NOAA.

Keywords

Theme Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > LAND SURFACE > TOPOGRAPHY > TERRAIN ELEVATION
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > BATHYMETRY/SEAFLOOR TOPOGRAPHY > SEAFLOOR TOPOGRAPHY
Global Change Master Directory (GCMD) Science Keywords
EARTH SCIENCE > OCEANS > COASTAL PROCESSES > COASTAL ELEVATION
ISO 19115 Topic Category
elevation
UNCONTROLLED
None DEM

Spatial Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Location Keywords
CONTINENT > NORTH AMERICA > UNITED STATES OF AMERICA
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > LAND SURFACE
Global Change Master Directory (GCMD) Location Keywords
VERTICAL LOCATION > SEA FLOOR

Instrument Keywords

Thesaurus Keyword
UNCONTROLLED
Global Change Master Directory (GCMD) Instrument Keywords Earth Remote Sensing Instruments > Active Remote Sensing > Profilers/Sounders > Lidar/Laser Sounders > LIDAR > Light Detection and Ranging

Platform Keywords

Thesaurus Keyword
Global Change Master Directory (GCMD) Platform Keywords
AIRCRAFT

Physical Location

Organization: Office for Coastal Management
City: Charleston
State/Province: SC

Data Set Information

Data Set Scope Code: Data Set
Data Set Type: Elevation
Maintenance Frequency: None Planned
Data Presentation Form: Elevation Data
Distribution Liability:

Any conclusions drawn from the analysis of this information are not the responsibility of NOAA, the National Geodetic Survey, the Coastal Services Center, or its partners.

Data Set Credit: Department of Commerce (DOC), National Oceanic and Atmospheric Administration (NOAA)

Support Roles

Data Steward

CC ID: 858203
Date Effective From: 2019
Date Effective To:
Contact (Organization): Office for Coastal Management (OCM)
Address: 2234 South Hobson Avenue
Charleston, SC 29405-2413
URL: https://www.coast.noaa.gov/

Distributor

CC ID: 858204
Date Effective From: 2019
Date Effective To:
Contact (Organization): Office for Coastal Management (OCM)
Address: 2234 South Hobson Avenue
Charleston, SC 29405-2413
URL: https://www.coast.noaa.gov/

Metadata Contact

CC ID: 858205
Date Effective From: 2019
Date Effective To:
Contact (Organization): Office for Coastal Management (OCM)
Address: 2234 South Hobson Avenue
Charleston, SC 29405-2413
URL: https://www.coast.noaa.gov/

Point of Contact

CC ID: 858206
Date Effective From: 2019
Date Effective To:
Contact (Organization): Office for Coastal Management (OCM)
Address: 2234 South Hobson Avenue
Charleston, SC 29405-2413
URL: https://www.coast.noaa.gov/

Extents

Currentness Reference: Ground Condition

Extent Group 1

Extent Group 1 / Geographic Area 1

CC ID: 1152865
W° Bound: -76.386945
E° Bound: -76.304493
N° Bound: 38.165636
S° Bound: 38.020557

Extent Group 1 / Time Frame 1

CC ID: 1152864
Time Frame Type: Discrete
Start: 2017-08-05

Spatial Information

Reference Systems

Reference System 1

CC ID: 1152862

Coordinate Reference System

CRS Type: Vertical
EPSG Code: EPSG:5703
EPSG Name: NAVD88 height
See Full Coordinate Reference System Information

Reference System 2

CC ID: 1152861

Coordinate Reference System

CRS Type: Projected
EPSG Code: EPSG:6347
EPSG Name: NAD83(2011) / UTM zone 18N
See Full Coordinate Reference System Information

Access Information

Security Class: Unclassified
Data Access Procedure:

Data is available online for custom downloads

Data Access Constraints:

None

Data Use Constraints:

Users should be aware that temporal changes may have occurred since this data set was collected and some parts of this data may no longer represent actual surface conditions. Users should not use this data for critical applications without a full awareness of its limitations.

Distribution Information

Distribution 1

CC ID: 858209
Start Date: 2019-07-01
End Date: Present
Download URL: https://coast.noaa.gov/dataviewer/#/lidar/search/where:ID=8778
Distributor: Office for Coastal Management (OCM) (2019 - Present)
File Name: Customized Download
Description:

Create custom data files by choosing data area, map projection, file format, etc. A new metadata will be produced to reflect your request using this record as a base.

File Type: Zip
Compression: Zip

Distribution 2

CC ID: 858210
Start Date: 2019-07-01
End Date: Present
Download URL: https://coast.noaa.gov/htdata/raster2/elevation/NGS_MD_StJeromesCreek_DEM_2017_8778
Distributor: Office for Coastal Management (OCM) (2019 - Present)
File Name: Bulk Download
Description:

Bulk download of data files in the original coordinate system.

File Type: img

URLs

URL 1

CC ID: 858198
URL: https://coast.noaa.gov/
Name: NOAA's Office for Coastal Management (OCM) website
URL Type:
Online Resource
File Resource Format: HTML
Description:

Information on the NOAA Office for Coastal Management (OCM)

URL 2

CC ID: 858199
URL: https://coast.noaa.gov/dataviewer/
Name: NOAA's Office for Coastal Management (OCM) Data Access Viewer (DAV)
URL Type:
Online Resource
File Resource Format: HTML
Description:

The Data Access Viewer (DAV) allows a user to search for and download elevation, imagery, and land cover data for the coastal U.S. and its territories. The data, hosted by the NOAA Office for Coastal Management, can be customized and requested for free download through a checkout interface. An email provides a link to the customized data, while the original data set is available through a link within the viewer.

URL 3

CC ID: 858200
URL: https://noaa-nos-coastal-lidar-pds.s3.amazonaws.com/laz/geoid12b/8777/supplemental/md2017_ngs_topobathy_stjeromecreek_m8777.kmz
Name: Browse graphic
URL Type:
Browse Graphic
File Resource Format: KML
Description:

This graphic displays the footprint for this lidar data set.

Technical Environment

Description:

OS Independent

Data Quality

Horizontal Positional Accuracy:

NOAA acquired and calibrated all lidar data and Dewberry classified this data and created derivative products. As such, Dewberry did not perform any absolute positional accuracy testing on this dataset. The DEMs are derived from the source lidar and inherit the accuracy of the source data. The DEMs are created using controlled and tested methods to limit the amount of error introduced during DEM production.

Vertical Positional Accuracy:

NOAA acquired and calibrated all lidar data and Dewberry classified this data and created derivative products. NOAA collected lidar data to meet 15cm vertical accuracy at 1 sigma. Dewberry did not perform any absolute positional accuracy testing on this dataset. The DEMs are derived from the source lidar and inherit the accuracy of the source data. The DEMs are created using controlled and tested methods to limit the amount of error introduced during DEM production.

Completeness Report:

Data covers the project boundary.

Conceptual Consistency:

Not applicable

Lineage

Lineage Statement:

Lidar was acquired by NOAA and processed by Dewberry.

Process Steps

Process Step 1

CC ID: 1152859
Description:

Data for the St. Jeromes Creek project was acquired by NOAA using a Riegl VQ880G sensor. All delivered lidar data is referenced to:

Horizontal Datum-NAD83 (2011) epoch: 2010

Projection-UTM Zone 18 North

Horizontal Units-meters

Vertical Datum-NAD83(2011) epoch: 2010

Vertical Units-meters

This dataset encompasses 342 500m x 500m tiles. Both green lidar data and NIR lidar data were acquired.

NOAA acquired, calibrated, and performed the refraction correction of the lidar data. Light travels at different speeds in air versus water and its direction of travel or angle is changed or refracted when entering the water column. The refraction correction process corrects for this difference by adjusting the depth (distance traveled) and horizontal position (change of angle/direction) of the lidar data acquired within water.

Dewberry received the calibrated green and NIR data and verified complete coverage. Relative accuracy of the green swaths compared to overlapping and adjacent green swaths as well as the relative accuracy of green swaths compared to overlapping and adjacent NIR swaths was verified through the use of Delta-Z (DZ) orthos created in GeoCue software. Intraswath or within a swath relative accuracy was verified using Quick Terrain Modeler. Profiles of elevated planar features, such as roofs, were used to verify horizontal alignment between overlapping swaths.

Dewberry used algorithms in TerraScan to create the intial ground/submerged topography surface.

Dewberry created 2-D breaklines by digitizing breaklines in a 2-D environment using intensity imagery as a reference. Dewberry used the 2-D breaklines to classify the bathymetric bottom and ground points properly in TerraScan.

All lidar data was peer-reviewed. Dewberry's QAQC also included creating void polygons for use during review. All necessary edits were applied to the dataset. GeoCue software was used to update LAS header information, including all projection and coordinate reference system information. The final lidar data is in LAS format 1.2 and point data record format 3.

The final classificaton scheme is as follows:

1-Unclassified

2-Ground

7-Topographic Noise

22-Bathymetric Noise

25-Water Column

26-Bathymetric Bottom

27-Water Surface

30-International Hydrograpic Organization (IHO) S-57 Object

All data was then verified by an Independent QC department within Dewberry. The independent QC was performed by separate analysts who did not perform manual classification or editing. The independent QC involved quantitative and qualitative reviews.

Process Date/Time: 2019-02-01 00:00:00
Process Contact: National Geodetic Survey (NGS)

Process Step 2

CC ID: 1152860
Description:

Dewberry made a copy of the final lidar data and transformed the data from ellipsoid heights to orthometric heights, referenced to NAVD88 Geoid 12B, meters. The lidar data in orthometric heights was used to create the final topobathymetric DEMs in orthometric heights

Lidar data was converted to a LAS Dataset. Lidar data classified as ground (2) and submerged topography (26) were then used to generate a raster in IMG format with 1 meter pixel resolution. The output raster was created over the full AOI area to reduce edge-matching issues and improve seamlessness. The raster was clipped to the tile grid and named according to project specifications to result in tiled topobathymetric DEMs.

All tiled DEMs incorporate the use of the void polygons. The void polygons represent bathymetric areas with no bathymetric bottom returns and are set as NoData in the DEMs. Void polygon creation is described in the final project report and the void polygon metadata.

A confidence layer has been created and provided to NOAA as part of the deliverables. Except where there are not enough lidar data points in a pixel to calulate a standard deviation value, the confidence layer is a raster product in IMG format with 1 meter square pixels. The confidence layer provides a standard deviation value for every pixel by calculating the standard deviation of all ground and/or submerged topography lidar points that are located within a single pixel. The confidence layer pixels align to the pixels in the topobathy DEMs. The confidence layer can be displayed by unique values or classified into desired bins/ranges for analysis over larger areas.

Process Date/Time: 2019-03-01 00:00:00

Catalog Details

Catalog Item ID: 56773
GUID: gov.noaa.nmfs.inport:56773
Metadata Record Created By: Maryellen Sault
Metadata Record Created: 2019-07-01 09:17+0000
Metadata Record Last Modified By: SysAdmin InPortAdmin
Metadata Record Last Modified: 2022-08-09 17:11+0000
Metadata Record Published: 2022-03-16
Owner Org: OCM
Metadata Publication Status: Published Externally
Do Not Publish?: N
Metadata Last Review Date: 2022-03-16
Metadata Review Frequency: 1 Year
Metadata Next Review Date: 2023-03-16